1. Field of the Invention
The present invention relates to a shape member manufacturing apparatus and a shape member manufacturing method capable of removing a joint projection remaining on the surfaces of the shape members to manufacture the surfaces of the shape members smoothly when a plurality of shape members are joined together by welding, friction stir welding, and the like.
2. Description of the Related Art
The shape members to be manufactured by the shape member manufacturing apparatus include, for example, extruded shape members made of aluminum alloy (hereinafter simply referred to as extruded shape members). The extruded shape members include, for example, ones having a flat plate-shaped shape member or a hollow shape member with ribs. In addition, the shape member manufacturing apparatus is manufactured to have a structure, which is obtained by making flat plates abut on each other and joining them together by welding. There are a structural body of a railway car as such manufactured from the extruded shape members. The structural body of a railway car is constructed with an underframe, side structures, a roof structure, and end structures. The side structure is manufactured by arranging a plurality of extruded shape members with their extruded direction extending along the longitudinal direction of the side structure, and by arranging the extruded shape members in the widthwise direction of the side structure for joining them together. The plurality of extruded shape members arranged in the widthwise direction of the side structure are joined together by welding or friction stir welding of abutting portions thereof. The roof structure or the underframe is manufactured almost in the same way as the side structure. When the adjacent extruded shape members are welded to each other, MIG welding is generally adopted, and welding beads protruding from the surfaces of the extruded shape members are formed at joints. Further, when the adjacent extruded shape members are joined together by the friction stir welding, projections are previously formed on the surfaces of joints of the respective extruded shape members, and the projections of both the abutting shape members are joined together by a tool for friction stir welding. The projections of both the abutting shape members are partially cut away by the tool for friction stir welding. However, the surfaces of the extruded shape members immediately after the welding do not become smooth because uncut portions remain. In this way, when the plurality of extruded shape members are butt-joined together by welding, friction stir welding, and the like, the protruding joint projections remain on the surfaces of the extruded shape members. The joint projections of the surfaces of the extruded shape members are smoothly manufactured by a manual operation using a grinder.
The operation of smoothing the surfaces of the extruded shape members is troublesome because it is a manual operation using a grinder. Further, a conventional smoothing operation is an operation that require skills because grinding should be performed in consideration of finished surfaces of the extruded shape members. Further, since the conventional smoothing operation requires much time and chip cuts are produced, the operation environment is bad.
Separately from the operation of smoothing the surfaces of the extruded shape members, an example in which surface manufacturing is performed on a plate member by mechanical devices is known in the Japanese Patent Laid-open No. 2000-158310 (Patent Document 1). Patent Document 1 discloses a deburring machine which performs deburring of a hollow portion caused by a turret punch and the like. However, finishing the joint projection continuously formed on the surfaces of the above-mentioned extruded shape members efficiently in a short time is not considered in this deburring machine.
Meanwhile, Japanese Patent No. 3070735 (Patent Document 2) discloses an example in which, when a plurality of extruded shape members are joined together by friction stir welding, a rear portion of a tool for friction stir welding is provided with a cutting device which cuts a joint projection. In this cutting device, an end mill is illustrated as an example of a cutting tool. When the joint projection is cut using the end mill, it is difficult to perform cutting while the tip of the end mill is caused to move along the surfaces of the extruded shape members accurately. Specifically, the total length of the side structure constructed by joining the plurality of extruded shape members together is as long as about 17 m to 25 m, and the width thereof is about 3 m. When cutting manufacturing is performed with the side structure constrained, in order to maintain the surface of the side structure in a flat state, a constraint device with high accuracy is needed on a large scale. Further, in order to cause a cutting means, such as an end mill, which cuts a joint projection on the surface of the side structure, a complicated control mechanism is required to move to follow the surface of the side structure accurately. For this reason, when the joint projection of the side structure and the like is automatically cut, it should be manufactured, leaving a cutting stock for finishing in consideration of cutting accuracy. In addition, finishing manufacturing should be performed on the cutting stock remaining on the surfaces of the extruded shape members by a manual operation using a grinder as previously mentioned.